Arthur Whitney (born October 20, 1957) is a Canadian computer scientist most notable for developing three programming languages inspired by APL: A+, k,[1] and q,[1] and for co-founding the U.S. companies Kx Systems[1][2] and Shakti Software.

[4][5] He also wrote the initial prototype of J, a terse and macro-heavy single page of code, in one afternoon, which then served as the model for J implementor, Roger Hui, and was responsible for suggesting the rank operators in J.

[8] At Morgan Stanley, Whitney developed A+[9] to facilitate migrating APL applications from IBM mainframe computers to a network of Sun Microsystems workstations.

In 1993, Whitney left Morgan Stanley and co-founded Kx Systems with Janet Lustgarten, to commercialize his k programming language.

The company signed an exclusive agreement with Union Bank of Switzerland and Whitney developed a variety of trading applications using k until the contract expired.